An implantable prosthetic heart valve is used as a replacement for a native heart valve of a patient. A typical prosthetic heart valve includes an annular valve orifice or body to provide a passageway for blood. At least one and usually two leaflets are mounted to an inner surface of the annular valve body and open or close with the flow of blood through the passageway.
A suture ring or sewing cuff is used to sew the heart valve to the patient's heart tissue. The sewing cuff is secured about the heart valve body in a circumferential groove and generally includes a biocompatible fabric suitable for allowing a needle and suture to pass therethrough. The sewing cuff is placed proximate the tissue annulus at the site of the excised native heart valve. Sutures are passed through the tissue annulus and the sewing cuff and tied snugly, thereby securing the valve to the heart.
Prosthetic heart valves are implanted wholly or partially within the tissue annulus of the excised native valve. To assure proper fit of the valve to the patient, the patient's tissue annulus must be "sized" to indicate the size of the valve to be implanted. In particular, proper fit of the annular valve body within the tissue annulus of the excised native valve is required. Commonly, a set of sizers is supplied by the prosthetic heart valve manufacturer corresponding to the different sizes of available prosthetic heart valves. After excision of the native valve, an attending physician uses the sizers to determine which corresponding prosthetic heart valve will be implanted. In order to assure that the proper prosthetic heart valve will be used, the attending physician usually must attempt to size the annulus several times with one or more sizers of different diameters until the best fit is recognized. The sizing procedure consumes valuable time during the operation.
Although described above with respect to a tissue annulus formed by excising a native heart valve, measurement of other anatomical tissue annuli such as arteries, veins and an esophagus, is desirable.